We intend to study the ultrastructural changes that accompany corneal reepithelialization. In particular, we will follow changes in connections between lateral cells (desmosomes) as well as connections between the basal epithelial cells and the basement membrane (hemidemosomes). We will also compare total corneal epithelial denudation which heals by migration of conjunctival epithelial cells, with partial corneal epithelial denudation which heals by the migration of corneal epithelial cells. Ultrastructural studies will also be performed on those completely denuded corneas which show delayed or abnormal reepithelialization. The role of the polymorphonuclear leucocytes which are invariably present after epithelial denudation, will be assessed by several means. We will attempt to increase the number of polymorphonuclear leucocytes in the corneal stroma by injecting irritants prior to epithelial denudation; we will also deplete the rabbit's circulating leucocytes by total-body X-irradiation with the head shielded to determine the effect of leucocyte depletion on corneal epithelial healing. We will measure the release of prostaglandins and thromboxanes from rabbit polymorphonuclear leucocytes and from conjunctival epithelial cells after a complete denudation of corneal epithelium. The effect of internal ocular inflammation (e.g. BSA or endotoxin induced uveitis) on corneal epithelial wound healing will also be investigated. We still determine if conjuctival inflammation produced by Compound 48/80 and concentrated soap solutions effect epithelial healing following complete denudation. Finally, we hope to screen a variety of agents, such as Vitamin E, retinoic acid, cholinergic agents and steroidal and non-steroidal anti-inflammatory agents with regard to their efficacy in speeding up reepithelialization. This approach will facilitate a better understanding of corneal epithelial non-healing problems so that appropriate therapy can be instituted.